Watershed Marching-Delineation Algorithm

2. The method of claim 1, wherein all other grid cells that flow through the cells with valid flow directions are the internal cells.

4. The method of claim 3, wherein for an initial cell v*, an incremental algorithm is guaranteed to find the adjacent lattice points belonging to Ω(v*).

5. The method of claim 4, wherein the HSM algorithm follows Proposition 1: Given an initial grid vertex v* with a valid flow direction in {20, 21. . . 27} at least one of the 4 adjacent lattice points will be coincident on a polygon boundary representing Ω(v*).

6. The method of claim 5, wherein the HSM algorithm further follows Proposition 2: Given the initial grid vertex v* with the valid flow direction in {21, 23, 25, 27}, an edge defined by coincident lattice points, between the initial grid vertex v* and a vertex, identifies a lattice location on the boundary of Ω(v*).

7. The method of claim 6, wherein the HSM algorithm further follows Proposition 3: Given the initial grid vertex v* with the valid flow direction in {21, 23, 25, 27}, the edge defined by the coincident lattice points marks the lattice location on the boundary of Ω(v*).

8. The method of claim 7, wherein the HSM algorithm further follows Proposition 4: Given the HSM algorithm follows a counterclockwise for lattice edges on Ω(v*) and one of four lattice neighbors is used to create an edge that separates Ω(v*).

9. The method of claim 8, wherein the HSM algorithm further follows Proposition 5: Given every lattice point belonging to Ω(v*) is visited at most twice.

11. The method of claim 10, wherein at each step of the march, the HSM algorithm identifies the valid march direction based on a Boolean inclusion condition, and wherein a vertex is deemed as exclusively on the boundary of the watershed when its discovery value is between original pour points discovery and finish value.

12. The method of claim 10, wherein based on the possible combinations of the BNP function calls and assuming the previous march step was towards north, if both BNP are True then the march will move to east, if both are false towards west, if a right hand cell is False and a left hand cell is True then towards north, and finally if the right hand cell is True and the left hand cell is False then the march can either move to west or to east.